Wildfire smoke is driving terrible air quality in major cities as new plumes arrive from Canada

Wildfires in Canada are pouring thick clouds of smoke into the US and will usher in unhealthy air quality for millions of people in Northeast and Midwest.

​ Wildfires in Canada are pouring thick clouds of smoke into the US and will usher in unhealthy air quality for millions of people in Northeast and Midwest. Read More Breaking News, Latest News and Videos | CNN